The invention disclosed relates to an improved dispensing head of the type used for batching foodstuffs under aseptic conditions, in particular, products of a paste-like consistency such as tomato puree.
The prior art embraces dispensing heads that comprise a vertically disposed chamber provided with a bottom outlet through which a product is fed into a container; such a container will be fashioned in a flexible material and pre-sterilized, and can hold several liters of the product. Positioned internally of and coaxial with the chamber, one has a vertical hollow plunger with a plug at bottom that registers in the outlet. Such a plunger can be shifted between two positions: raised, with the plug distanced from the outlet, and lowered, with the plug locating in and thus blocking the outlet.
The plug will normally occupy the raised position, in particular when the product is batched into the container, and on completion of the filling operation, move into the lowered position whereupon inert gas is caused to flow under pressure into the bore of the plunger. The effect of such a step is that residual foodstuff clinging to the outlet will be pushed into the container, and the internal surface of the outlet is thus maintained free of matter that might become contaminated during changeover of the container, or putrefy if allowed to linger in the outlet for any length of time.
The plug also keeps the outlet closed off during changeover of the container, thereby keeping the chamber separate from the surrounding environment.
Problems nevertheless occur in the prior art embodiment described above, due to blockages caused by residual foodstuff that accumulates in the bore of the plug. Passage of the inert fluid through the bore is obstructed, if not totally impeded, by the accumulated matter, thus jeopardizing the plug's efficient operation; what is more, such accumulated foodstuff necessarily becomes exposed to the surrounding environment during changeover of the container, and one has the risk of putrefaction.
Drawbacks are likewise in evidence where the dispensing head is used to fill containers that have undergone an internal pre-sterilization and are thus offered to the head with stopper already inserted. The dispensing head is provided with appropriate means that remove the stopper from the neck of the container prior to its being filled, and replace it thereafter. Such means are located internally of an aseptic enclosure in which sterilizing fluid is held at pressure marginally above atmospheric, and which encapsulates the bottom outlet of the chamber. The base of the enclosure is provided with an opening, coaxial with the chamber outlet, for the purpose of accommodating the neck of the container.
The drawbacks in question arise from the fact that the outer surfaces of the stopper and the neck of the container will have been exposed to the surrounding environment, and when offered ultimately to the dispensing head, may be contaminated to a degree against which the sterilizing power of the enclosure is insufficient.
The object of the invention, accordingly, is that of overcoming the problems and drawbacks encountered with prior art type dispensing heads.